Fat is an important part of the diet of all individuals. It serves as a source of energy and essential fatty acids, and also as a carrier for fat-soluble vitamins. In addition, due to its unique functional properties, fat is often used to improve the overall quality of foods including color, texture, structure, flavor, mouthfeel and other characteristics.
However, both the total desirable amount of fat and types of fat in the diets of individuals have been a subject of controversy. A number of investigations revealed a correlation between high consumption of fats and increased rates of atherosclerosis, coronary artery disease and obesity. As a result, several organizations, including the American Heart Association, U.S. Department of Agriculture and Department of Health, have recommended the reduction of total fat intake in general and of saturated fat in particular.
The nutritional and biological effects of fatty acids are diverse. As long as 30 years ago, it was observed that diets composed predominantly of saturated fatty acids increased plasma lipids, whereas diets containing polyunsaturated fats decreased plasma lipids. More recent findings indicate that even monounsaturated fatty acids, such as oleic acid, can be hypolipidemic. F.H. Mattson and S.M. Grundy, J. Lipid Res., 6:194 (1985). It is now well accepted that not only the total amount of fat, but also the composition of dietary fat which is consumed affects the incidence of coronary arterial disease.
The relative proportion of saturated to unsaturated fats consumed in the U.S. has changed significantly. The consumption of fats derived from vegetable oils that are rich in unsaturated fatty acids has more than doubled in the last 50 years. R.L. Rizek, et al., In Dietary Fats add Health, E.G. Health and W.J. Vesek, (eds.) American Oil Chemists' Society, Champaign, II., p. 17 (1983). However, in a number of food products, the complete substitution of saturated fats with unsaturated fats is often problematic. The functional properties of fats in different foods are determined by a number of parameters, including the balance between solid and liquid phases and the structure of the fat crystal.
Fats can crystallize into different crystal forms. The consistency, plasticity, graininess, and other physical properties of many products such as butter, lard, margarine, shortenings, and cocoa butter, all depend on a particular polymorphic form of the triglyceride present. As a result, only a certain part of solid saturated fat can be substituted with liquid unsaturated oils without sacrificing the sensory quality of the product.
An alternative material that can mimic the physical and structural properties of saturated fats without having unfavorable nutritional qualities would be valuable for reducing the amount of saturated fat in a food product without sacrificing the sensory quality of the food product.
Summary of the Invention
The invention relates to an oil or fat which contains a polymeric, fat-soluble material and its use for the modification of the physical properties of fats and oils. The polymeric material be used in the present invention includes non-nitrogen containing, oil-soluble polymers, such as alkyd-type polyesters, polymers based on hydroxyacids and natural polymers, such as cutin, poly(vinyl esters), polyglycol esters and polyacrylates. Alkyd-type polyesters are particularly useful in the present invention.
The polymers are used in fat formulations wherein all or a portion of the fat is substituted by a mixture or an emulsion containing a liquid fat and the polymer. Naturally occurring oils, synthetic oils, fat mimetics or combinations thereof can be used in the present invention. In one embodiment, the polymeric, fat-soluble material is used as a texturing agent for oils. The polymer is added to neat oils to change the physical characteristics of the oils, such as the melting point and viscosity. Liquid oils composed of mostly unsaturated fatty acids solidify or form gels at room temperature in the presence of even small amounts of the polymer.
The polymer also helps to stabilize and solidify emulsions. In this embodiment, the polymer is incorporated into an oil-in-water or water-in-oil emulsion, forming a material having the physical and structural characteristics of saturated fat but which contains no saturated fat.
The present oils or emulsions treated with the oil-soluble polymers can be used to reduce the amount of saturated fat in foods. Use of the present treated oils or emulsions allows all or part of the saturated fat in a food to be replaced by unsaturated oils while still retaining desirable sensory or physical qualities of the food product.